Compact and Wide Stopband Dual-mode LTCC Filter for 5G N79 Band Applications

A compact and wide stopband dual-mode bandpass filter (BPF) utilizing Low Temperature Co-fired Ceramic (LTCC) packaging package is proposed and verified for the fifth-generation (5G) mobile communications applications. The proposed BPF is constructed using stacked U-shaped clip lines (SUCLs) and a dual-mode resonator. The BPF is realized in a 3-layer LTCC substrate and its entire size is only 0.2×0.2×0.008 λg with a size reduction of 65%. Moreover, the BPF possess a broad stopband up to 5th-order harmonic with a minimal 20 dB suppression. Discussion and comparison are executed as well.